The present invention relates to an information recording medium for realizing a high-value-added article, such as a prepaid card, a gift certificate, a bond certificate, a software package or the like, with additional control information for preventing counterfeiting, an information reader for reading information from the information recording medium, an information recording medium transfer foil, and a method of fabricating the information recording medium.
Prepaid cards and cash cards are information recording mediums. Prepaid cards include telephone cards issued by NTT (Nippon Telegraph and Telephone Co.), pinball game cards issued by Japan Card System Co. and commute tickets, tickets and prepaid cards issued by transportation companies. Cash cards include bank cash cards issued by banks and credit cards issued by credit institutions.
When checking up whether an information recording card is authentic, magnetic data recorded on the information recording card is read and checked or a portrait attached to the information recording card or a hologram recorded on the information recording card is examined. Control information relating to the fabrication and use of the information recording card including date of fabrication, the number of message units, a secret number and the like is recorded magnetically and the magnetic data is rewritten.
Bar codes representing control information and recorded by advanced printing technology or holography are used to prevent counterfeiting gift certificates, beer tokens, certificates, such as stock certificates and public bond certificates, and the like.
Holograms are used in recent years to authenticate pieces of software, such as computer programs.
Nevertheless, those high-value-added articles are subject to counterfeiting and dishonest alteration that cause a significant social problem.
An invention, xe2x80x9cRecording Card and Authenticity Identifying Apparatusxe2x80x9d (Japanese Patent Application No. Hei 5-094846) applied for patent by Iwasaki Tushinki K.K. (Conventional art 1) is measures to prevent the counterfeiting and dishonest alteration of the information recorded on prepaid cards and cash cards.
The recording card of the conventional art 1 has an ordinary first magnetic recording region, and a second recording region of an amorphous ferromagnetic layer. A security code is recorded in the second recording region. The authenticity identifying apparatus is capable of magnetically detecting punched holes indicating the number of message units or the like. Therefore, the dishonest alteration of the recorded information, such as concealing the punched holes by a screening member, can be easily found. The security code written to the second recording region is unrewritable and inerasable and hence the authenticity of the recording card can be identified by the security code.
An invention, xe2x80x9cinformation recording mediumxe2x80x9d (Japanese Patent Application No. Hei 8-276878, Sep. 30, 1998) applied for patent by Iwasaki Tushinki K.K. (Conventional art 2) is an information recording medium having, in combination, an amorphous ferromagnetic thin film and a hologram.
The conventional art 2 uses the amorphous ferromagnetic thin film and the hologram in combination. The information recorded in the amorphous ferromagnetic thin film can be magnetically read.
An invention, xe2x80x9cMagnetic Plate with Magnetic Pattern and Method of fabricating the Samexe2x80x9d (Japanese Patent Application No. Hei 8-231288, filed Aug. 14, 1998) applied for patent by Iwasaki Tushinki K.K. (Conventional art 3) is a method capable of easily adding signals to those magnetic members.
The conventional art 3 applies an ink to a surface of a flat base sheet or forms projections or depressions in a part of the surface of the flat base sheet by a chemical or physical method to form a smooth blank region and a pattern region respectively having different magnetic characteristics, and uses the difference between the blank region and the pattern region for the magnetic reading of recorded information.
A hologram is used to prevent counterfeiting, for example, by placing a diffraction grating having ridges and furrows of sizes on the order of micrometers on a surface of a film, forming a metal thin film over the diffraction grating and producing a characteristic pattern, such as a three-dimensional image or an interference color. A metal that reflects light moderately, such as inexpensive aluminum, is used and any magnetic metal is not used. The formation of the minute ridges and furrows of sizes on the order of micrometers requires highly advanced techniques and such ridges and furrows cannot be easily counterfeited. Nevertheless, such minute ridges and furrows have been counterfeited in recent years.
A method of writing magnetic data relating to the prior art 2 (xe2x80x9cInformation Recording Mediumxe2x80x9d, Japanese Patent Application No. Hei 3-27687) uses magnetic members of different materials or records information by an arrangement of magnetic members. Thus, an amorphous magnetic material must be used and signals must be written to a magnetic member in addition to a hologram.
It is an object of the present invention to provide an information recording medium free of the disadvantage of the conventional high-added-value articles, such as prepaid cards, cash cards and certificates, that the conventional high added-value articles can be comparatively easily counterfeited or forged and capable of being easily attached or transferred to cards and various high-added-value articles, an information reader for reading information recorded on the information recording medium, an information recording medium transfer foil and a method of fabricating the information recording medium.
According to a first aspect of the present invention, an information recording medium comprises: a base member; a resin layer having a surface having a pattern region provided with a three-dimensional diffraction grating or a holographic pattern; and a ferromagnetic thin film formed on the resin layer; wherein the ferromagnetic thin film has a magnetic characteristic dependent on the diffraction grating or the holographic pattern of the pattern region.
An information reader according to a second aspect of the present invention that reads information recorded on an information recording medium comprising a base member, a resin layer having a pattern region provided with a three-dimensional diffraction grating or a holographic pattern, and a ferromagnetic thin film formed on the resin layer, wherein the ferromagnetic thin film has a magnetic characteristic subject to the diffraction grating or the holographic pattern of the pattern region, comprises: an exciting means for ac-exciting the pattern region of the information recording medium in a predetermined direction; a magnetic head means for scanning the pattern region along the predetermined direction and reading the variation of magnetic flux provided by the information recording medium excited by ac-excitation; and a driving means for driving the information recording medium relative to the magnetic head means or the magnetic head means relative to the information recording medium to move the information recording medium or the magnetic head continuously or intermittently at a moving speed far lower than the scanning speed of the magnetic head means in a feed direction perpendicular to a scanning direction in which the magnetic head means moves relative to the information recording medium for scanning.
The information reader may further comprise a read pattern storing means for reading output signals provided by the magnetic head means in synchronism with the scanning operation of the magnetic head means and the driving operation of the driving means and temporarily storing a read pattern corresponding to the diffraction grating or the holographic pattern formed in the pattern region; a reference pattern storing means for storing an output signal provided by the magnetic head means and corresponding to the diffraction grating or the holographic pattern of a reference pattern region as a reference pattern; and a comparing means for comparing the read pattern read and stored in the pattern storing means and the reference pattern stored in the reference pattern storing means; wherein the authenticity of the information recording medium is verified by the magnetic characteristic of the ferromagnetic thin film determined on the basis of the result of comparison made by the comparing means.
According to a third aspect of the present invention, a counterfeiting preventing sheet comprises: an information recording medium including a base member, a resin layer having a pattern region provided with a three-dimensional diffraction grating or a holographic pattern, and a ferromagnetic thin film overlying the resin layer and having a magnetic characteristic dependent on the diffraction grating or the holographic pattern of the pattern region; and a backing sheet in which the information recording medium is embedded; wherein the backing sheet has open parts formed at intervals to expose parts of the information recording medium therein, and covering parts extending between the open parts to cover parts of the information recording medium.
According to a fourth aspect of the present invention, an information recording medium transfer foil comprises: a base member; a resin layer formed on the base member and having a pattern region provided with a three-dimensional diffraction grating or a holographic pattern; a ferromagnetic thin film formed on the resin layer; and a heat-sealable layer or an adhesive layer formed on the ferromagnetic thin film; wherein the ferromagnetic thin film has a magnetic characteristic dependent on the diffraction grating or the holographic pattern of the pattern region.
According to a fifth aspect of the present invention, an information recording medium fabricating method comprises the steps of: fabricating an information recording medium transfer foil comprising a base member, a resin layer having a pattern region provided with a three-dimensional diffraction grating or a holographic pattern, a ferromagnetic thin film formed on the resin layer and having a magnetic characteristic dependent on the diffraction grating or the holographic pattern of the pattern region, and a heat-sealable layer or an adhesive layer formed on the ferromagnetic thin film; and transferring the information recording medium transfer foil to a carrying medium.